1. Field of the Invention
The present invention relates to an endoscope provided with an observation optical system of an object contact type which brings a distal end portion of an objective optical system in contact with an object to observe the same.
2. Description of the Related Art
Jpn. Pat. Appln. KOKAI Publication No. 2005-640 (Patent Document 1) discloses an endoscope provided with an observation optical system of an object contact type and an ordinary observation optical system. The observation optical system of an object contact type brings a distal end portion of an objective optical system in contact with an object to observe the same. The ordinary observation optical system observes an object in a non-contact state of the objective optical system with the same. Here, the endoscope disclosed in Patent Document 1 includes a projecting portion projecting forward provided on a distal end face of an insertion portion of the endoscope. The observation optical system of an object contact type is disposed on an end face of the projecting portion. Further, an observation window of the ordinary observation optical system, windows of a plurality of illumination optical systems, a air-feeding/water-feeding nozzle, an distal end opening of a treatment tool insertion channel, and the like are disposed on an end face on a proximal end side of the projecting portion of the insertion portion. Illumination light is emitted ahead of the endoscope from an illumination window of the illumination optical system on the end face on the proximal end side of the projecting portion. The illumination light is used as illumination light for the ordinary observation optical system and is also used as illumination light for the observation optical system of an object contact type.
Jpn. Pat. Appln. KOKAI Publication No. 2002-238835 (Patent Document 2) shows an endoscope having a configuration where a projecting portion projecting forward is provided on a distal end face of an insertion portion of the endoscope. Here, an observation window of an observation optical system, an illumination window of an illumination optical system, a distal end opening of a first treatment tool insertion channel, and the like are disposed on an end face of the projecting portion at the distal end face of the insertion portion. Further, a distal end opening of a second treatment tool insertion channel is disposed on an end face on a root side of the projecting portion of the insertion portion.